#define _CRT_SECURE_NO_WARNINGS 1
class Solution {
public:
    const int MAX = 0x3f3f3f3f;
    int maxProfit(vector<int>& p) {
        int n = p.size();
        vector<vector<int>> f(n, vector(3, -MAX));
        auto g = f;
        f[0][0] = -p[0], g[0][0] = 0;
        for (int i = 1;i < n;i++)
        {
            for (int j = 0;j < 3;j++)
            {
                f[i][j] = max(f[i - 1][j], g[i - 1][j] - p[i]);
                g[i][j] = g[i - 1][j];
                if (j - 1 >= 0)
                    g[i][j] = max(g[i - 1][j], f[i - 1][j - 1] + p[i]);
            }
        }
        int ret = 0;
        for (int i = 0;i < 3;i++)
            ret = max(ret, g[n - 1][i]);
        return ret;
    }
};